Construction of g- C3N4/Au/MgAl2O4 photocatalysts with different coupling methods to improve the photodegradation behavior and performance prediction

Abstract

A novel g-C3N4/Au/MgAl2O4 (CN-Au-MAO) system have been developed to improve the photocatalytic activity of CN and MAO for the simulated sunlight -driven chlortetracycline hydrochloride (CTC-HCl) removal. The Au particles act as a surface plasmon resonance center to separate and accumulate electrons from the conduction band of CN and MAO, promoting the transfer of photo-generated carriers, thereby maintaining high oxidative capacities of MAO. The prepared photocatalysts revealed that the plasma resonance wavelength and photocatalytic efficiency of CN -Au -MAO photocatalysts strongly depend on the coupling order of CN, Au, and MAO. The effects of mass percentages of Au, CN and Au-CN, catalyst content, drug concentration and pH value on the degradation of CTC-HCl were explored in depth. The CN-Au-MAO photocatalysts exhibited a high photocatalytic efficiency of 92.56% toward the photodegradation of CTC-HCl with the optimum catalyst content of 1 g/L, drug concentration of 200 mg/L and pH= 11. The genetic algorithm was used to predict the photocatalytic activity of CN-Au-MAO photocatalyst, and the minimum data set that can effectively predict its photocatalytic activity was explored. The active species detection experiments, degradation pathways, and toxicity estimates were also performed. A reasonable mechanism of the CN-Au-MAO system was proposed. This work effectively solves the problem of coupling MAO with the noble metal particles, which makes MAO easy to hydrolyze, and the problem of predicting the effective minimum data set required for the photocatalytic activity through neural network algorithms.